Mobile devices such as mobile phones, smartphones, and game machines have adopted 3D display devices that display 3D images by using binocular parallax. When these 3D display devices are used, there are cases in which an object in the 3D space needs to be indicated. Generally, an object in the 3D space can be indicated by moving a position indication marker such as a cursor or a pointer on an image. Such a position indication marker that uses an arrow or the like on an image for indicating the position of an operation target is called in various ways such as a cursor, a pointer, etc. In the present description, such a position indication marker will be referred to as a cursor. Namely, in the present description, a position indication marker such as a pointer will collectively be referred as a cursor.
Conventional 3D display devices use various methods for indicating an object in the 3D space. These methods can be divided into two kinds.
In a first method, a cursor is also displayed with a depth in the 3D space. To move this cursor, a control operation system in the depth direction is prepared in addition to two-dimensional control in horizontal and vertical directions. In this way, coordinates in the 3D space are directly indicated. For example, FIG. 4 in Patent Literature 1 (PTL 1) discloses moving a pointer (a cursor) in the 3D space by using a key and a switch, more specifically, an arrow key 32 and a Y-axis seesaw switch 31.
A second method is based on the same idea as indicating an object with an operator's finger in the real world. Since the finger is near and the object is far, when the operator focuses on the object, it appears to the operator as if there were two fingers. However, human left and right eyes recognize an object differently (an eye mainly used for recognition will hereinafter be referred to as a dominant eye). Thus, in the second method, an object is determined by using the image of a finger viewed by a dominant eye as a finger pointing in the correct direction.
PTL 2 discloses a 3D object operating method for providing a natural operating environment. According to PTL 2, an object in the line of sight of a dominant eye, which is a right eye or a left eye, is selected as an object corresponding to a cursor. As disclosed in FIG. 5 in PTL 2, if the operator sees with his/her right eye only, it appears to the operator that a cursor position 506 overlaps an operating point 502 of an object A (501). In addition, if the operator sees with his/her left eye only, it appears to the operator that the cursor position 506 overlaps an operating point 504 of an object B (503). PTL 2 discloses that the operator selects an operating point viewed by the operator's dominant eye as a desired operating point of the operator. For example, in the example in FIG. 5 in PTL 2, if the right eye is the dominant eye of the operator, the operating point 502 is selected as a desired operating point of the operator. If the left eye is the dominant eye, the operating point 504 is selected as a desired operating point of the operator.
In addition, PTL 3 discloses adjusting the stereoscopic effect of a generated image and changing the appearance of the object space by adjusting the distance between the left eye viewpoint and the right eye viewpoint and by changing the depth of the line of sight.
[PTL 1]
Japanese Patent Kokai Publication No. 2011-153995A
[PTL 2]
Japanese Patent Kokai Publication No. 2004-362218A
[PTL 3]
Japanese Patent Kokai Publication No. 2003-107603A